New argument --exclude-player-metrics

README.md

@@ -37,6 +37,7 @@ Flag | Variable | Default | Help
 --port | A2S_EXPORTER_PORT | 9841 | Port for the metrics exporter.
 --path | A2S_EXPORTER_PATH | /metrics | Path for the metrics exporter.
 --namespace | A2S_EXPORTER_NAMESPACE | a2s | Namespace prefix for all exported a2s metrics.
+--exclude-player-metrics | A2S_EXPORTER_EXCLUDE_PLAYER_METRICS | false | If true, exclude all `player_*` metrics. This option may be necessary for some servers.
 --a2s-only-metrics | A2S_EXPORTER_A2S_ONLY_METRICS | false | If true, excludes Go runtime and promhttp metrics.
 --max-packet-size | A2S_EXPORTER_MAX_PACKET_SIZE | 1400 | Advanced option to set a non-standard max packet size of the A2S query server.
 

internal/collector/collector.go

@@ -9,15 +9,16 @@ import (
 )
 
 type Collector struct {
-	addr          string
-	clientOptions []func(*a2s.Client) error
-	client        *a2s.Client
-	descs         map[string]*prometheus.Desc
+	addr                 string
+	clientOptions        []func(*a2s.Client) error
+	excludePlayerMetrics bool
+	client               *a2s.Client
+	descs                map[string]*prometheus.Desc
 }
 
 type adder func(name string, value float64, labelValues ...string)
 
-func New(namespace, addr string, clientOptions ...func(*a2s.Client) error) *Collector {
+func New(namespace, addr string, excludePlayerMetrics bool, clientOptions ...func(*a2s.Client) error) *Collector {
 	descs := make(map[string]*prometheus.Desc)
 
 	fullDesc := func(name, help string, labels []string) {
@@ -54,9 +55,10 @@ func New(namespace, addr string, clientOptions ...func(*a2s.Client) error) *Coll
 	playerDesc("player_the_ship_money", "Player's money in a The Ship server.")
 
 	return &Collector{
-		addr:          addr,
-		clientOptions: clientOptions,
-		descs:         descs,
+		addr:                 addr,
+		clientOptions:        clientOptions,
+		excludePlayerMetrics: excludePlayerMetrics,
+		descs:                descs,
 	}
 }
 
@@ -67,7 +69,7 @@ func (c *Collector) Describe(descs chan<- *prometheus.Desc) {
 }
 
 func (c *Collector) Collect(metrics chan<- prometheus.Metric) {
-	serverInfo, playerInfo := c.queryInfo()
+	serverInfo, playerInfo := c.queryInfo(c.excludePlayerMetrics)
 
 	truthyFloat := func(v interface{}) float64 {
 		if reflect.ValueOf(v).IsNil() {
@@ -81,7 +83,10 @@ func (c *Collector) Collect(metrics chan<- prometheus.Metric) {
 	}
 
 	add("server_up", truthyFloat(serverInfo))
-	add("player_up", truthyFloat(playerInfo))
+
+	if !c.excludePlayerMetrics {
+		add("player_up", truthyFloat(playerInfo))
+	}
 
 	addPreLabelled := func(name string, value float64, labelValues ...string) {
 		labelValues2 := []string{serverInfo.Name}
@@ -94,7 +99,7 @@ func (c *Collector) Collect(metrics chan<- prometheus.Metric) {
 }
 
 // queryInfo queries the A2S server over UDP. Failure will result in one or both of the return values being nil.
-func (c *Collector) queryInfo() (serverInfo *a2s.ServerInfo, playerInfo *a2s.PlayerInfo) {
+func (c *Collector) queryInfo(excludePlayerMetrics bool) (serverInfo *a2s.ServerInfo, playerInfo *a2s.PlayerInfo) {
 	var err error
 
 	// Lazy initialization of UDP client.
@@ -113,6 +118,10 @@ func (c *Collector) queryInfo() (serverInfo *a2s.ServerInfo, playerInfo *a2s.Pla
 		return
 	}
 
+	if excludePlayerMetrics {
+		return
+	}
+
 	// A quirk of the a2s-go client is that in order for The Ship player queries to succeed, the client must be
 	// constructed with The Ship App ID.
 	playerClient := c.client

internal/collector/collector_test.go

@@ -19,7 +19,7 @@ import (
 // TestCollector_Describe_PrintTable tests the Describe function.
 // It also prints a Markdown-formatted table of all registered metrics, which can be copied to the README.
 func TestCollector_Describe_PrintTable(t *testing.T) {
-	c := collector.New("", "")
+	c := collector.New("", "", false)
 	descs := testDescribe(c)
 	if len(descs) == 0 {
 		t.Error("expected Descs but got none")
@@ -97,7 +97,7 @@ func TestCollector(t *testing.T) {
 
 	// Set up the registry and gather metrics from the test A2S server.
 	registry := prometheus.NewPedanticRegistry()
-	registry.MustRegister(collector.New("", conn.LocalAddr().String()))
+	registry.MustRegister(collector.New("", conn.LocalAddr().String(), false))
 	metrics, err := registry.Gather()
 	if err != nil {
 		t.Fatal(err)
@@ -119,6 +119,68 @@ func TestCollector(t *testing.T) {
 	)
 }
 
+func TestCollector_ExcludePlayerMetrics(t *testing.T) {
+	// Run a test A2S server.
+	conn, err := net.ListenUDP("udp", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv := &testserver.TestServer{
+		ServerInfo: &a2s.ServerInfo{
+			Name:       "foo",
+			Players:    3,
+			MaxPlayers: 6,
+		},
+		PlayerInfo: &a2s.PlayerInfo{
+			Count: 3,
+			Players: []*a2s.Player{
+				{
+					Index:    0,
+					Name:     "jon",
+					Duration: 32,
+				},
+				{
+					Index:    0,
+					Name:     "alice",
+					Duration: 64,
+				},
+				// Duplicate players should be de-duplicated to avoid causing registry errors.
+				{
+					Index:    0,
+					Name:     "alice",
+					Duration: 99,
+				},
+			},
+		},
+	}
+	go func() {
+		t.Error(srv.Serve(conn))
+	}()
+
+	// Set up the registry and gather metrics from the test A2S server.
+	registry := prometheus.NewPedanticRegistry()
+	registry.MustRegister(collector.New("", conn.LocalAddr().String(), true))
+	metrics, err := registry.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Spot check the gathered metrics.
+
+	testAssertGauge(t, metrics, "server_players",
+		expectGauge{value: 3, labels: map[string]string{"server_name": "foo"}},
+	)
+	testAssertGauge(t, metrics, "server_max_players",
+		expectGauge{value: 6, labels: map[string]string{"server_name": "foo"}},
+	)
+
+	for _, family := range metrics {
+		if strings.HasPrefix(*family.Name, "player_") {
+			t.Errorf("metric name %s should have been excluded", *family.Name)
+		}
+	}
+}
+
 type expectGauge struct {
 	value  float64
 	labels map[string]string

main.go

@@ -24,7 +24,8 @@ func main() {
 	port := flag.Int("port", envOrDefaultInt("A2S_EXPORTER_PORT", 9841), "Port for the metrics exporter.")
 	path := flag.String("path", envOrDefault("A2S_EXPORTER_PATH", "/metrics"), "Path for the metrics exporter.")
 	namespace := flag.String("namespace", envOrDefault("A2S_EXPORTER_NAMESPACE", "a2s"), "Namespace prefix for all exported a2s metrics.")
-	a2sOnlyMetrics := flag.Bool("a2s-only-metrics", envOrDefaultBool("A2S_EXPORTER_A2S_ONLY_METRICS", false), "If true, skips exporting Go runtime metrics.")
+	excludePlayerMetrics := flag.Bool("exclude-player-metrics", envOrDefaultBool("A2S_EXPORTER_EXCLUDE_PLAYER_METRICS", false), "If true, exclude all `player_*` metrics. This option may be necessary for some servers.")
+	a2sOnlyMetrics := flag.Bool("a2s-only-metrics", envOrDefaultBool("A2S_EXPORTER_A2S_ONLY_METRICS", false), "If true, excludes Go runtime and promhttp metrics.")
 	maxPacketSize := flag.Int("max-packet-size", envOrDefaultInt("A2S_EXPORTER_MAX_PACKET_SIZE", 1400), "Advanced option to set a non-standard max packet size of the A2S query server.")
 	help := flag.Bool("h", false, "Show help.")
 	version := flag.Bool("version", false, "Show build version.")
@@ -62,7 +63,7 @@ func main() {
 	clientOptions := []func(*a2s.Client) error{
 		a2s.SetMaxPacketSize(uint32(*maxPacketSize)),
 	}
-	registry.MustRegister(collector.New(*namespace, *address, clientOptions...))
+	registry.MustRegister(collector.New(*namespace, *address, *excludePlayerMetrics, clientOptions...))
 
 	// Set up http handler.
 	handler := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})